Yamaha Outboard Lower Unit Rebuild | Yamaha F225 Lower Unit Rebuild  | Boats.net

Yamaha Outboard Lower Unit Rebuild | Yamaha F225 Lower Unit Rebuild | Boats.net

John Talley here with Boats.net. Today
i’m going to walk you through building a lower unit for our 2004 F225, and we’re
gonna do it from scratch. So I’m gonna walk through every single thing you need
to check as far as your shimming, and then checking the backlash to get this
thing put back together and back on the water. So, let’s head over to the table,
look at all the parts and the tools we’re going to be using to get this
project done. As you can tell from this table, my parts list is really extensive.
What I’m about to do it wouldn’t make sense for you to do if you had as much
damage as the unit. You would just call us, and replace it– get a whole new Yamaha
unit ready to go and you just bolt it back to your power head. What I’m going
to show you is the shimming process that will be required if you were just
replacing your lower unit housing and putting in all your original equipment. I
mean, that happens very often: you break off a skeg, you don’t want to trust a
weld– let’s go ahead and replace just the housing itself. Conversely, if you were
just replacing just one of your bearings, or just one of your gears. You would
still need to go through the shimming process and that’s what i’m gonna walk
you through. So we’ve looked at all the parts, let’s look at these special tools
that you’re going to need to get this done. Now any common hand tools that
you’re gonna have, I’m not gonna call those out. I will tell you what size it
is as we go along– but the specialty tools I’ve got laid on the table right
now, and let’s go through it. The one specialty Yamaha tool that you’re going
to need is this. Now it is required so you can get a starting point for your
shims for the forward and reverse gears. Also you’re gonna need a feeler gauge so
you can take those measurements. Next you’re going to need a puller. It doesn’t
have to be an extreme one, it just needs to be one that can put pressure on your
output shaft housing. Next you’re going to need to pick up a caliper. Also will
get a bearing a driver set. Next you’re going to need a torque wrench that can
at least go to a hundred and three foot-pounds. Beyond that, you’re going to
need a slide hammer puller. Make sure that the jaws can be oriented in 180
degrees and they can get down through roughly an inch diameter. Last but not
least you’re going to need a magnetic base depth gauge. It doesn’t have to be a
digital one like this, but it just needs to measure the
difference from a calibrated zero. Makes it a lot easier with an articulated arm
and a magnetic base. You’ll see that later. So, with what you see on this table is
how I’m going to pull this off. There is one special tool that Yamaha makes that
I’m not going to use. It is actually a unit that gives you a beginning shim
size for the pinion gear. Now this one tool is north of $500, and if you’re like
me, I don’t want to spend 500 if I’m gonna rebuild the lower unit.
It just wouldn’t make sense to do so. So we’re gonna do this without that tool.
Now do I have access to that one? Yeah, I do. But what’s the point? I’m gonna show
you how to do it in your own garage with just these tools. So, now that we’ve got
all our parts and our tools together let’s head over there and get started. So step number one with this process:
let’s go over to either your new housing or your existing housing and up under
where the the trim tab would be there are a set of numbers that we’re after.
And you’re gonna see an F for forward, an R for reverse, and then a P for
pinion. And then there’s going to be a plus or minus followed by a number. What
that is is a deviation from the exact perfect zero that they’ve measured on
this particular housing. So we want to write down these three numbers. F in my
case is going to be plus 06, reverse is plus 06, and P is plus 01. Now
those are going to be our deviation numbers. You’re actually going– they’re
going to be in millimeters, so you’re going to divide them by 100 to get the
number of millimeters. That’s be point zero six, point zero six, point zero one. What
we’re gonna use to do this is a flat surface, the flattest you can find
because the more accurate you are here the less chances there’s going to be
you’re gonna have to go back and change out the shims when we actually measure
the backlash. So what we’re gonna be after is the forward gear taper bearing.
And we want to face it up like this. See how they’re tapered in? Now what we’re
looking for to put into our final equation is that distance right inside
of here. Now the thickest gauge I have is actually 0.889 millimeters. So if that
fits through there too easily we may have to sandwich in a thinner one
until we get at that particular distance here. So let’s try the 0.889 and hold
this just as flat as you can. Just a light touch, because we don’t want it
rocking back and forth we want it flat against the the granite. Alright that
goes through there but just barely. I’m not quite moving the bearing surface
and that’s what I’m kind of looking for. When it starts to move just a tick? That
tells me that I’m there. So balance that again.
Let’s bring over a point zero five one and see if that
slides through together. Alright those both go through and it’s still not
moving. Let’s bump it up. Let’s go ahead and go out to a point one millimeters
and see if that starts to catch. Alright see how that’s starting to move my
bearing a little bit holding it flat? That’s just barely moving it so I think
we’ve got a winner there. To get the M-0 to fill into the equation down below,
we’re going to take point five five, and we’re going to take that point 06 in
millimeters, and that’s going to come out to point four four millimeters. So
that’s our M-0 number. So we’ve got our .99 minus .44 so that leaves
this .55 millimeters and that’s what we want our shims to be. So
we’re going to end up at least having two of them in there. Out of our
available shim thicknesses, we don’t have a .55. So we’re gonna have to
add two of them together. So what we’re gonna do is take both 0.4 and 0.15. Those
together? 0.55. So we’re getting ready to drive these in. We’re gonna put in our
shims first, then we’re gonna drive this in and we’re gonna use a taper bearing
driver to get that done. Whatever driver you’re using, make sure
it does have this edge, and also make sure it’s out of aluminum because we do
not want a steel one to damage the surface. ‘Cause that surface right there?
That’s your bearing surface. We do not want to mar that. Get our sims down into
position all the way down at the very front. Now we can take our outer race. Let’s see if we can drive it in. Uh-huh, that was a noise we were waiting
for. that’s the sound of success. She should be bottomed now. Bet you it is.
That’s all the way down. So next we’re gonna set up for the forward bearing and the
trick here is to find a spacer or an insert that’s going to catch it just on
the inner part of the race because that’s what we need to push against. You
don’t want to push against the actual carrier that’s holding all the needle
surfaces. So we’re gonna face that down, get our gear in place, and using the same
driver we used earlier, push all that together. That should do.
Alright guys, before we can measure for the shim thickness we need to go and
install the prop shaft main bearing. Just choose the correct driver and we want to
make sure it has contact with the outer part of the bearing. The other thing you
need to note is the markings it has for where it was manufactured and possibly
the part number? We want those to actually face in. That should do. Let’s go
over to the table and take that measurement. It’s basically the same as
we did for the forward. This time we’re actually flipping the tool upside down
and we’re wanting to measure this M. And even on the largest one I have, which is
back at that .889, it’s still not nearly big enough to fill that
gap. So we’re gonna end up sandwiching them together until we can get this
measurement. I’m getting really close. Starting to rub, I think we can call
that one right there. So our deviation from the housing itself
was 0.44 millimeters, so we measured the M using our gauge at 1.6
millimeters. So, T2 is going to be M minus M0 which is one point six minus 0.44,
which gives us 1.16 millimeters. So to get there we’re gonna
go with two point five millimeters, and then we’re going to add in a point one
five. Now that we know the shims for the forward and reverse, we can go ahead and
start to put things back together because we’re not going to use that $500
tool to determine the shims for it the pinion. We’re actually just going to pick
one in the middle and determine if we’re higher or low and hopefully our forward
and reverse will be equal distance or off as far as whether we need to lift
the pinion gear up or if we need to drop it down. Because what you’re basically
looking at here is this is your forward gear, if this is a pinion gear coming
down, and this is the reverse gear. Those are the three variables we’re having to
line up right there. So as long as we know this is right, and we know this is
right, then we can just adjust this one up or down till we get the correct
backlash. That is what we’re after. Now that we’ve chosen the two sets of shims
that can be determined, we can go ahead and start putting it together and see
where we end up on the backlash and then adjust the pinion from there. Sounds easy,
right? Well, let’s keep going. So we’ve got our shims, get them in place. We’ve got
our housing and we’re actually going to be pressing it against this surface and
not the very bottom. We’re using a driver that just fits on top of these dog gears.
That should do. Let’s push her in. That should do. I’m not
super thrilled about doing it this way. I really should have driven in that needle
bearing before I put on this gear, but we are where we are. So what we’re gonna use
it’s just a block of wood so we don’t scar any of the surface because that’s
extremely important that it not get damaged. What we’re gonna do is use just
a twenty seven millimeter socket. What I’m actually going to do is spin it
around backwards with an extension that way I can help keep it squared as we’re
driving it in. Also they want you to have the markings where it says Japan and
NSK facing out. Let’s drop that in place, get in our socket. Let’s see if we
can drive this in go in till she bottoms. That’s it.
Don’t push anymore ’cause that’s a really thin wall and we don’t want to damage it. There we go. Alright now we can continue.
As soon as you take out this cardboard piece, all these little needle bearings
are invariably gonna fall out. So what I usually do is take a little bit
of light grease, go around the casing, and then reinstall them, which I’m doing now.
Because otherwise when we go to put this in, they’re gonna fall out. With that
grease in place, we can actually remove this. We have less of a chance that the
needles actually falling out. So you’re going to use just a length of threaded
rod, three bolts, couple of washers, and a socket to pull this thing in place. So
this piece is going to go up top. And down below we’re going to bring it
up into position with just a socket and a bolt that’s going to be going through
it– through the thread rod and the whole section’s gonna bring it, pull it up.
You’ll notice on the outer casing has lettering and they want that facing down.
So the way we’re going to tackle this with all these different moving pieces,
we’re gonna rotate this up. That way we’ll have gravity helping us instead of
hindering us. So bring it up. Everything looks lined up. Let’s see if we can get
it to pull in. Looks like it’s going straight. Yep.
If you hit a bunch of resistance right from the beginning, that means it’s not
going in straight. So back off, drop it back out, and try again. This is looking
pretty promising. We’re just gonna bring it up until it stops. You don’t have to
force it any further. Should be getting close now. There it is.
Snug it down, she is set. Even with that grease I still did have
one or two needle bearings fall out. I’m just gonna get fish them out, pop them
back in, no problem. Just be mindful of that as we’re putting this together if
you hear a tink in the bottom? That means you probably lost one and you’re going
to need to extract it and get it back in there– until we get that input shaft put
in there which will hold everything in place. So next we’re going to install our
drive shaft, input shaft specifically, but here’s the real trick: we do not have and
we’re not going to use that $500 special tool that measures the distance in
between in here in here. More specifically, the variation caused by the
manufacturing process of the shaft. Now we know that the housing itself for the
pinion has just a +1 variance, so that means that it’s really really close. So
the big question is, we’re gonna take a shot in the dark as to which one is
going to be the correct thickness. I’m gonna kind of head toward the lower end
because I want to actually be able to put the unit together. So when we do that
and we measure the backlash, that will tell me– providing that the distance on
the reverse and the forward gears is equally out– that’ll tell me the distance
that this one needs to either go up or come back down to where I’ll have
everything in alignment. So with all that being said, let’s go ahead and
assemble it. So you’ve got your bearing, spacer, our shim to be determined, and then
our housing. Now if you need help putting together this housing, we actually did
that in a separate video, so reference it and it’ll tell you and show you the
depth that the bearing and then the seals are supposed to be pressed into
this. So before we get our input shaft in place, let’s go ahead and get that
forward gear in. So let’s go ahead and lower in our input shaft. But don’t let
it go all the way down ’cause we need to go ahead and get our pinion gear on along
with its washer and nut. Our washer and our bolt, just put it on hand tight, then
we’ll come back and bring the housing down. As you’re tightening down the upper
housing, just be leery there may be some play. Want to make sure that there is
play as we’re bringing it down. That’ll tell us if that front shim, the forward
shim, is actually within the ballpark. It should be. Let’s go ahead and grab the
adapter and then we’re gonna torque it down to, I believe it’s 103
foot pounds. There she is. So next up we need to get the output
shaft put together– or the prop shaft put together. Before I do that I have to put
together the shift assembly. So all of these springs and washers and clips go
on this little shift assembly but it actually goes up into the shifter, and
acts as a detent with these two ball bearings that’s gonna allow it actually
just shift back and forth. Complicated little device. Feel like I’m building a
watch. There we go. Now these two shift plungers they
actually face each other. The beveled edge is pointing to each other. Then our
spring, and this washer, and then this other piece goes on. So if we can
actually get this to go in together without sending it flying around the
room I’ll be impressed. There we go, fun. Take this assembly, drop
it in here. Now what you need to do actually is line
up these two beveled areas with these two holes because that’s where the ball
bearings are gonna go. Those are placed into here into the
shaft. The actual shifter slides onto here. And now push the entire assembly in
and then rotate it so that is visible through here. Now we can take the clutch
dog and get it in place. Make sure that F is going toward the front. Now you can
put your pin through. Now you can take your cross pin spring– if you want to
call it that– and wind it around and that will hold your pin in place. There we go. Let’s go ahead and get our
seals, and our new prop shaft housing, and these both go in back-to-back like this.
And we’re gonna set them right at five millimeters deep. Now if you need
specific instructions on how to do this, we actually did this in an earlier video
so you want to check that out I can walk you through the process step-by-step. You don’t have to get carried away right
here, just to help get it in there and one day somebody will actually be
pulling this apart to probably replace the seals so we want to make it a is
easy for them as possible. More than likely, we’ll be the first ones to
pull it back out. So we’ve got a prop shaft housing ready to go. Let’s go and
get our output shaft in place. Don’t forget this washer. A little bit more
grease just on this running surface. So let’s go ahead and get it in place. Now we can get our prop shaft housing in. My initial feeling so far is we’re loose.
Kind of expected it to be, but that’s okay. That means I’m gonna be able to
take a measurement and that’s going to tell me how many more shims we’re gonna
need. Before we do that I’ve got to build up the shift shaft, get it installed, then
we’ll set it up and take a measurement. So we’ve got our seal popped in, got our
shift shaft ready to go, just putting a little bit of grease on this pivot
points. Got on our clip, our spring. Alright,
let’s go get it installed. Now let’s see if we can drop her in there. That should
be it. Now when you’re putting this in, don’t forget this little washer back
here. Otherwise you have a– not gonna pick up your water like you’re supposed to,
it’ll leak. Get in our three bolts and we’ll be ready to check it. I’m gonna get
this plate, then we’re gonna bring over a dial indicator with a little tab that
we’re gonna mount to the input shaft. And that’s going to give us a measurement as
to whether how tight or loose we are for both the forward and reverse. And the way we’re
going to do this is either apply pressure pulling out or pushing in on
the output shaft and that’ll give us zero tolerance where we can measure
whatever gap that there is for the forward and reverse. So to recap what we
have on the forward gear is a shim account of 0.55 millimeters. On the
reverse, we have one point one five millimeters. And for the pinion gear, just
shooting out of the out of the gate, we have a point four millimeter. So to
measure the forward, what we want to do is put pressure pushing the output shaft
into the forward gear. To do that, we’re going to use our puller
and we’re just going to tighten it up until the point that it can’t be rotated. We’re gonna set up our gauge, then we’re
gonna flip it upside down and then get that a little bit of lash reading–
hopefully there is one everything’s not set too tight. I don’t think that it is.
Alright. Bring it back, zero it. The range we were
looking for was .21 to .44 millimeters. So if we’re just a
little bit loose on the forward. So now, let’s set up, measure the reverse, and
see where we ended up. So now we’re going to measure the reverse gear backlash, and
to do that we’re going to apply the opposite pressure to the output
shaft itself. Right now we’re pushing in on it. What we’re gonna do is take a
propeller, not install that forward spacer, that way it will actually be pulling out
on the output shaft itself. And that way we can measure that shim thickness and
see if it needs to be adjusted. So the hope here is that the measurement
will end up being loose as well. That way we’ll only have to adjust the pinion to get
it to come down a little bit and give us the necessary clearance. Now if it’s too
tight? Then I’m gonna have to rework all of this. But hopefully, they’re both loose,
this can come down, and that’ll get it into spec. So you take the prop, you do
not put the spacer in at this point. You actually take your spacer instead of
having it on the back side you put it on the front side here along with the
washer. Then we’re going to tighten it down
until she holds still. That should do it. Yep, that’s what we’re after. Now let’s
flip it around. 1.52, so yes, she’s definitely loose. Okay,
so using the equation for the forward gear, what we’re going to do is calculate
the change we’re going to make on the pinion instead. Now he’s going to show
the equation on the on the screen. that’s going to be M minus 0.33 and they’re
going to multiply that times the .71 So we get the .53
minus .33 equals 0.2 times that .71. So we need to
adjust it by .14 millimeters. So the new shim stack is going to be
.54 or as close as we can get to it, .55 That’s what
we’re gonna actually go for. We’re gonna pull it back apart, we’re gonna change
out those pinion shims to 0.54 or as close as I can get to it.
We’re gonna go recheck the forward, make sure we’re still within where we want to
be, and then we’re gonna do the reverse see where it ends up, and then adjust
accordingly to those shims. A little bit of a drawn-out process, but I’m gonna get
you there. So here we are. We’ve got a .4 in
there, and we want to take it to a .54 total. So we’re gonna add a
.15, which is the 20 to this. Hopefully that’ll get us on line
for the forward gear and then we’ll see what we need to adjust on the reverse. Always make sure before I put them in there.
If you get too many shims laying around, sometimes I can be a bad thing. So let’s go back together and see where
we end up. Hopefully this would be the last time we’re putting the pinion gear
together. Alright, 103 coming up. Throwing out my
back. Good stuff. Alright let’s get our housing back in. Looking good. We’re at
0.40. So we’re in there. Just barely, but we’re in there because we had a range of
0.21 to 0.44. I’m gonna go with that, especially because right now there’s no
fluid in there and when I fill it up it’s gonna actually going to close that
gap a little bit more. So I’m good with it being a little bit toward the loose
side. So let’s reconfigure it and see where we ended up on the reverse side. So
let’s get our prop on, get that snug down and we’ll see what we
ended up. Alright she’s she’s way too loose. 1.45. So we’re going to use the
different equation. So it’s gonna be our measured, which is 1.45 minus the
0.87 times 0.71. So we need to change it by 0.41. So we’re going to end up 1.15
is what we had in there, so we want to end up somewhere around 1.56 total. So we’re gonna increase it by 0.4. So that should be pretty easy to
find. Just a .4 and cram it in there see where we end up. Alright the
shims stayed in there so we don’t have to worry about that. Let’s get this
pulled apart, get that .4 in there, re-measure. Alright let’s go. So
let’s step over to the press. We want to make sure this bearing didn’t get pulled
up any. I’m gonna push it back down just to make sure. Then I’m gonna press this
on and we’ll see where we ended up. Yep, it shifted. Just slightly. So doing this
was very important. Dead-on. 0.93. Alright guys, that’s what
we’re looking for. We want to go ahead and get all the measuring devices, take
off the prop, then you just want to feel the output shaft. Because I’ve actually
measured these and it tells me I’m right in the ballpark, and you couldn’t move
the shaft. It was just too tight. All that was measuring as it should. That may be
the reason the Yamaha changed their measuring procedure on this particular
model. But I’ve been doing this particular format for a long time and
it’s always served me pretty well. Alright,
that’s with everything removed. Yeah, it’s got a little bit of resistance to
it but nothing that I can’t turn with my fingers. Alright guys that pretty much
wraps this one up. Only thing I have left to do now is do a pressure test and fill
it up with fluid, and actually we have a couple of videos that show you how to do
that. So if you need that information, why don’t you reference those videos.
Listen if you need any parts for your boat why don’t you come see us at Boats.net and we can get you taken care of. You have any questions or comments, leave
them in the section below and I’ll do my best to answer them. We just want to say
thanks for shopping here with us at Boats.net and we will see you in the
next video. Have a great day.